What is a myeloproliferative neoplasm (MPN)?
Myeloproliferative neoplasms (MPNs) are blood disorders in which the bone marrow makes too many of one or more types of blood cells — white blood cells, red blood cells or platelets. Normally, our bone marrow makes the cells that circulate in our blood. It is within the bone marrow that blood stem cells (immature cells) become mature blood cells over time.
MPNs are rare and often need care from specialists with deep experience in blood disorders. At Penn Medicine, hematologist-oncologists provide expert blood cancer care, combining advanced diagnostics with research-driven treatment approaches. Our team has helped shape the field of hematology, including the discovery of the Philadelphia chromosome, which first linked a genetic change to cancer. This experience helps guide more precise diagnosis and care.
Types of myeloproliferative neoplasms
The type of myeloproliferative neoplasm is based on whether too many red blood cells, white blood cells, or platelets are being made.
- Chronic myelogenous leukemia (CML), in which immature cells that would be red blood cells, white blood cells, or platelets overtake the bone marrow and blood.
- Essential thrombocythemia, in which too many platelets are made in the bone marrow
- Myelofibrosis (also called primary or chronic idiopathic myelofibrosis), in which abnormal blood cells and scarring build up within the bone marrow
- Polycythemia vera, in which too many red blood cells are formed in the bone marrow
Chronic myeloproliferative disorders sometimes can become acute leukemia, in which too many immature abnormal white blood cells are made. This is a rare event. Other, less common, myeloproliferative disorders include:
- Chronic eosinophilic leukemia
- Chronic neutrophilic leukemia
- Mastocytosis
- Myeloproliferative/myelodysplastic syndromes
- Neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB, or FGFR1 genes
Why myeloproliferative neoplasms develop
Myeloproliferative neoplasms develop when changes occur in the genes that control how blood cells grow and divide. These changes can cause the bone marrow to make too many blood cells.
The exact cause isn’t always clear. Some research suggests a link to high levels of radiation or exposure to certain chemicals, like benzene. Other researchers are looking into whether viral infections or other environmental triggers cause the genetic code in bone marrow cells to change. While we don’t have definitive proof of a single cause yet, research continues to bring us closer to an answer.
Symptoms of myeloproliferative disorders
Symptoms vary with each type of myeloproliferative neoplasm. Common symptoms, similar to leukemia symptoms, include but are not limited to:
- Pale skin
- Shortness of breath
- Lethargy (tiredness)
- Night sweats
- Unexplained weight loss or loss of appetite
- Enlarged spleen
- Vision or hearing problems
- Fever
- Bruising or bleeding easily
Tests used to diagnose MPNs
Blood tests and a physical exam are often the first steps in diagnosing myeloproliferative neoplasms. Additional tests may examine the blood and bone marrow more closely to confirm the diagnosis. The Penn Medicine hematopathology service is a national leader in diagnosing neoplastic and reactive hematologic disorders, with broad expertise in MPNs. Working closely with the clinical team, Penn hematopathologists provide integrative, state-of-the-art analysis using histology and a wide range of advanced techniques.
Care and treatment for MPNs
Many people with myeloproliferative neoplasms don’t need active treatment right away. When treatment is needed, your care team will recommend options based on your specific condition, symptoms, and overall health.
Specialized care for myeloproliferative neoplasms
Blood cancers like MPNs can be complex. At Penn Medicine, you’ll have access to a full range of treatment options, along with clinical trials that may offer promising new therapies. A dedicated care team helps coordinate appointments, answer questions, and support you through each step. Our long history in blood cancer research and treatment helps bring the latest advances into everyday care, even for the most challenging cases.
Rated “exceptional” by The National Cancer Institute
Penn Medicine’s Abramson Cancer Center is a world leader in cancer research, patient care, and education. Our status as a national leader in cancer care is reflected in our continuous designation as a Comprehensive Cancer Center by the National Cancer Institute (NCI) since 1973, one of 7 such centers in the United States. The ACC is also a member of the National Comprehensive Cancer Network, one of a select few cancer centers in the U.S., that are working to promote equitable access to high-quality, advanced cancer care.